Once taken for granted, the stability and dependability of the nation’s power grid can no longer be assured. The situation in the mid-Atlantic region is especially worrisome.

Measures are being taken to protect the electricity infrastructure from weather-related outages, cyber attacks and sniper attacks like the one at a power station in San Jose, Calif. But nothing has been done to prevent a loss of reliable electric power that could result from prematurely shutting down large power plants — both coal and nuclear — that supply base-load power 24/7.

Regional transmission organizations and state public utility commissions need to recognize that the loss of a large number of nuclear power plants due to economic reasons is a real possibility. Recently, Peter Lyons, the U.S. Department of Energy’s assistant secretary for nuclear energy, warned that 30 percent of the U.S. nuclear fleet of approximately 100 nuclear plants might be shut down.

Nuclear power supplies about one-fifth of the nation’s electricity and almost 52 percent of the power in New Jersey. A typical plant like Oyster Creek produces power approximately 90 percent of the time, in response to demand for electricity. By contrast, a coal plant supplies power on average 70 percent of the time and a combined-cycle natural gas plant, 60 percent. Solar and wind power – which are subject to variable weather conditions — can be counted on to produce electricity no more than 20 percent of the time.

Although it’s a safe and reliable source of electricity, nuclear power in some parts of the country can’t compete with cheap natural gas and subsidized renewable energy. This matters because nuclear power has attributes that are not being recognized in unregulated energy markets such as the one that exists in New Jersey, Maryland and Pennsylvania. Nuclear power gets no credit for producing about 20 percent of our national supply of electricity with no resultant carbon dioxide (greenhouse gas) emissions. Nor does it get any credit for providing voltage support to the grid. And nuclear power provides a hedge against soaring natural gas prices.

Witness the volatility of gas prices this winter in New England and the mid-Atlantic. Spot prices for immediate delivery of natural gas reached $140 per million BTUs. Usually, gas sells for approximately $4 per million BTUs. Unless you think gas prices will stay at $4 for the next 20 to 40 years, there is no rational economic reason for shutting down the Vermont Yankee nuclear power plant or the Kewaunee nuclear plant in Wisconsin. Yet both plants are slated to be shut down by the end of this year. And Exelon, which owns the largest fleet of nuclear plants in the United States, has warned that it might need to shut down its Clinton and Quad Cities plants in Illinois due to economic reasons.

If a reliable nuclear plant that delivers base-load electricity around the clock is taken out of commercial service, we have a problem – even more so when other sources of energy, such as coal, are stressed as well. Certainly, here in the mid-Atlantic region, we can’t afford to lose the Three Mile Island and Oyster Creek nuclear plants, but that could happen unless the grid operator and state public utility commission take action to preserve a balanced mix of energy sources. Our region already relies on natural gas for a growing share of its electricity, but with households and industries requiring gas, supplies can become constrained.

That might sound strange in an era of shale gas abundance. But even with a lot of gas in the ground, there is heavy demand for it combined with a shortage of pipelines, processing facilities and other infrastructure that can cause price spikes, as they did this winter in New England.

Since the Energy Information Administration forecasts a need for 339,000 megawatts of new electric capacity by 2040 — and there is no telling how many nuclear plants could close before then – we should not underestimate the potential damage to our economic and environmental health, and damage to our electric grid, if there isn’t enough power from base-load plants to provide voltage support, helping to maintain grid stability.